Sinatra's Github Repository
Ok, I got what you're really asking. Your posted question is too different from what you're asking.
Well, there are many factors to consider in knowing if the library is actively maintained, like
- how quickly the application is kept updated.
- how many days before a high bug / issue is resolved
- is the documentation is rich / updated (a library without documentation is practically useless)
- how many user's website are using it
- does your model developers (those whom you look up to) have favorable view on the library. Their opinion matters since they have the years of experience o evaluate the application
Well, that's what I've though (and there's more). I hope this helps.